This invention relates to the art of the two-wheel roller skate. A review of prior art literature discloses a long history of worldwide interest and effort in this subject dating from the earliest days of the roller skate industry and covering a wide range of skate designs and roller types. Yet, the two-wheel roller skate has never achieved true success, and the critical problem still remains, how to make this type of skate fully maneuverable and safe.
Maneuverability in a roller skate requires an efficient and reliable system for mechanical turning of the roller assemblies. This problem was solved in the case of four-wheel skates by the introduction of the double-action turning mechanism commonly used in all such skates today. It is a leverage-oriented system ideally suited to the nature of four-wheel skates where there are two cylindrical rollers in each roller assembly thus allowing an optimum degree of lateral roller stability for the skater to work with in generating the leverage force needed to operate the turning mechanism.
It is a different matter, however, in the case of two-wheel roller skates where there is only one roller per assembly thereby severely limiting the degree of lateral roller stability available to the skater in producing the necessary leverage force. If a conventional double-action turning mechanism is to be effectively employed in a two-wheel roller skate then it is necessary to provide a roller that can better address the needs for both lateral mobility and improved lateral stability in a single roller.
In the prior art of two-wheel roller skates, attempts have been made in the past to arrange a suitable wheel assembly, as for example, in the Holliday, et al U.S. Pat. No. 4,047,727, where there is provided a central roller wheel with a pair of frustoconical independent rotatable end portions. There are other disclosures in the art of frustoconical rollers, as for example in the Goodwin Pat. No. 3,282,598 where a single unitary roller construction is disclosed, the two conical sections of the roller abutting at the center in a defined V-shaped edge. Other examples are seen in Japanese Pat. No. 52,6241 to Morita which discloses a single roller of somewhat barrel shape having one continuous arcuate surface with recessed grooves therein.